The invention described herein may be manufactured and used by the U.S. Government for Governmental purposes without the payment of any royalty thereon.
1. Field of the Invention
The present invention relates to a method for fabricating body heating and cooling garments.
2. Description of Prior Art
Military personnel, astronauts and other persons operating in extreme temperature environments typically require a heating or cooling garment. Typically, such garments are air and vapor permeable and comprise synthetic tubing that carries cooling or heating fluid medium. The tubing is in close body contact so as to effect transfer of the heat or cold to the wearer of the garment.
The heating or cooling garment can be configured into different shapes and sizes. For example, many heating or cooling garments are typically configured as vests. The garment utilizes tubing that is attached to a liner. Since pressures within the tubing can reach 100 p.s.i. (pounds/square inch), the mating of the tubing to its substrate must be fluid pressure-insensitive. The liner is then attached to a fabric which forms the outer portion of the garment. These garments are preferably stretchable and flexible to conform to the shape of the body of the individual. Furthermore, these garments provide mobility for arms and legs, and retain the tubing close to the body for more efficient transfer of heat or cold. The flexibility produces relatively less damage to the tubing during garment flexure and substantially reduces the likelihood of punctures or tears to the garment. Moreover, there is a requirement that these garments be relatively lightweight and easy to clean.
One conventional method for fabricating these garments involves sewing the tubing to a substrate or liner which is sufficiently porous to allow internal vapors to escape as well as to provide for air permeability. However, a significant problem with sewing the tubing is referred to as “needle holing”. Needle holing requires that every inch of the tubing be sewn to the porous substrate. Such a technique significantly increases the risk of puncturing the tubing during the sewing process. Furthermore, the threads themselves provide a major irritant when the tubes are pressed into contact with the body. Additionally, the sewing method is slow and expensive. Automated sewing techniques are not viable options due to the difficulty of achieving registration of the tubing with predetermined patterns.
Another disadvantage of stitching or sewing arises when chemical protective clothing is being fabricated. In such a situation, stitching the tubing to any substrate results in needle holes that permit unwanted chemicals to move from one side of the garment to the other. One conventional technique used in an attempt to eliminate this problem with sewing or stitching is to fabricate the heating/cooling garments with a bladder sealed at its edges wherein the cooling fluid is contained within the bladder. However, while bladder-type garments do in fact conduct heat away from the body or conduct heat to the body, the resulting garment is non-breathable, non-stretchable and non-flexible due to the two-coated fabrics which are joined together by heat. Furthermore, flexibility of the garment is impeded when a relatively large volume of liquid is captured in the garment. Additionally, only conduction can be used to remove heat since a bladder-type garment poses an impermeable barrier against natural perspiration. Therefore, the bladder-type cooling garment completely eliminates the possibility of evaporative or convective cooling. A further disadvantage of the bladder-type garments is that the edges of the bladder deteriorate when subjected to pressures higher than 30 psi.
There are other conventional methods for attach tubing to a liner or substrate. One such method involves brushing or rolling adhesives onto liners to adhere the tubing to liners. However, all lining porosity is destroyed when the adhesive is massively applied across the substrate.
Another conventional technique is to use adhesive tape to secure the tubing to the liner. Specifically, the adhesive tape contacts the liner to either side of the tube along its length. This technique is exceedingly difficult to implement due to the fact that when the tubing is formed around small radius corners, the overlying strip of tape has to be notched in order to follow the tubing around the corners. Furthermore, tape impedes the ability of the garment to stretch and also degrades garment permeability. Additionally, tape does not always sufficiently adhere the tubing to the liner.
What is needed is a new and improved method for making such a heating and cooling garment that solves the problems mentioned in the foregoing discussion that are associated with conventional methods and also provides all the desirable characteristics such as flexibility and permeability. Furthermore, such a new and improved method should result in a relatively lower per-unit manufacturing cost of the garment.